We sought to characterize ALS patients who opt for tracheostomy and long-term mechanical ventilation (LTMV) and compare them with respect to medical, psychiatric, and psychosocial measures to patients who declined tracheostomy and died. We studied 72 ALS patients who were identified as hospice-eligible. They were assessed monthly until the endpoint of death or tracheostomy. LTMV patients continued to be followed for up to 55 months. The spouse or other caregiver was similarly interviewed and followed. Medical and psychiatric evaluations were conducted, in addition to self-reported depressive symptoms, future orientation, attitudes about hastened death, religious beliefs, and quality of life. Global cognitive capacity was assessed by caregivers. Fourteen patients chose LTMV; 58 died without LTMV. At study entry, those who later chose LTMV were younger, more had young children, had more education, and higher household incomes on average. Although their physical conditions were similar, they reported higher levels of optimism including belief in imminent cure, and more positive appraisals of their ability to function in daily life, their physical health and overall life satisfaction. At study entry, none who later chose LTMV were clinically depressed, compared to 26% of those who later refused LTMV, and their mean scores on the Beck Depression Inventory were in the "not depressed" range while the mean for patients who later died was in the "probable depression" range. Fourteen percent of patients who later chose LTMV were reported by caregivers to have had at least mild cognitive problems, compared to 49% of those who later died. After an average of 33 months on LTMV, only about half retained high levels of optimism and enjoyment of daily life, independent of residence (home vs. facility). Two patients expressed interest in hastening death but none had asked to terminate ventilation despite disease progression. However, half identified future circumstances that would render life intolerable. At last contact with caregivers, only one LTMV patient was reported to have major cognitive impairment. While reporting substantial emotional burden after LTMV, most but not all spousal caregivers continued to express satisfaction with care-giving. Our findings suggest that the choice of LTMV was not about desperation (although it may involve unrealistic expectations of cure by some), ignorance, or inability to make wishes clear during a chaotic dying period. Rather, LTMV choice was consistent with a sustained sense that life was worth living in any way possible, at least for some time and within certain boundaries. ALS clinicians will need to recognize this motivation and provide appropriate clinical education to both patient and family.